Systems and methods for providing ultrasound guidance to target structures within a body

ABSTRACT

An ultrasonic probe comprising a housing, a first ultrasonic transducer array, a second ultrasonic transducer array, a first light source, and a second light source. The first ultrasonic transducer array is coupled to the housing and configured to emit a first planar ultrasonic beam in a first direction within a first plane. The second ultrasonic transducer array is coupled to the housing and configured to emit a second planar ultrasonic beam in the first direction within a second plane, which is substantially perpendicular to the first plane. The first light source is coupled to the housing and configured to project a first light line substantially within the first plane. The second light source is coupled to the housing and configured to project a second light line within a third plane, which is substantially perpendicular to the first plane and intersects the second plane at an oblique angle. The first light line intersects and is substantially perpendicular to the second light line.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims the benefit of U.S. Provisional PatentApplication No. 62/212,586, filed on Aug. 31, 2015, which isincorporated by reference in its entirety.

FIELD OF THE INVENTION

This invention relates generally to ultrasound probes and, moreparticularly, to an ultrasound probe having guidance light sources andmethods of directing an instrument from a surface to a target structurebeneath the surface.

BACKGROUND

Ultrasound is a medical imaging tool that, in certain implementations,permits health care practitioners to locate and visualize internalbodily structures, such as blood vessels and internal organs. When theseinternal structures need to be accessed, ultrasound is sometimes used todirect an instrument toward the target structure. For example,ultrasound may be used for to assist with venous line placement,arterial line placement, biopsy, drainage, ablation, or otherinterventions.

Unfortunately, despite the improvements in ultrasound technology, aswell as training and operator skills, it is still difficult to reliablyand continuously direct the instrument to the target structure withoutcomplications. While an improvement over unguided approaches, currentultrasound probes are still limited in the guidance that they provide.

It should be appreciated that there is a need for an ultrasound probethat enables heath care practitioners to safely perform proceduresinvolving internal bodily structures with greater ease and accuracy andfewer complications. The probe should reliably and continuously directan instrument from a surface to a target structure beneath the surface.The present invention fulfills these needs and provides further relatedadvantages.

BRIEF SUMMARY OF THE INVENTION

The present invention is embodied in an ultrasonic probe, which includesa housing, a first ultrasonic transducer array, a second ultrasonictransducer array, a first light source, and a second light source. Thefirst ultrasonic transducer array is coupled to the housing andconfigured to emit a first planar ultrasonic beam in a first directionwithin a first plane. The second ultrasonic transducer array is coupledto the housing and configured to emit a second planar ultrasonic beam inthe first direction within a second plane, which is substantiallyperpendicular to the first plane. The first light source is coupled tothe housing and configured to project a first light line substantiallywithin the first plane. The second light source is coupled to thehousing and configured to project a second light line within a thirdplane, which is substantially perpendicular to the first plane andintersects the second plane at an oblique angle. The first light lineintersects and is substantially perpendicular to the second light line.

In one embodiment, the ultrasound probe is embodied in a handhelddevice. In another embodiment, the first and second ultrasonictransducer arrays are arranged in a T-shaped configuration.

In one embodiment, the first light source is a first laser and thesecond light source is a second laser. In another embodiment, the secondlaser is configured to project the second light line within the thirdplane at a projection angle, wherein the projection angle is less than90°. In an additional embodiment, a stepper motor coupled to the secondlaser. In a further embodiment, the stepper motor is configured torotate the second laser and thereby adjust the projection angle, whereinthe adjusted projection angle is less than 90°. In yet anotherembodiment, a position of the second laser relative to the first laseris adjustable.

In one embodiment, the ultrasound probe further includes a controlpanel. In another embodiment, the control panel includes a touch screen.In a further embodiment, the ultrasound probe includes a screen coupledto the ultrasound probe and configured to display both a first imagefrom the first ultrasonic transducer array and a second image from thesecond ultrasonic transducer array. In an additional embodiment, thescreen is configured to display a centerline. In another embodiment, thecenterline corresponds to a center of the second ultrasonic transducerarray. In yet another embodiment, the centerline corresponds to a pointof intersection between the first ultrasonic transducer array and thesecond ultrasonic transducer array.

In one embodiment, the ultrasound probe further comprises a sterilecover coupled to the ultrasonic probe. In another embodiment, thesterile cover comprises a rigid, optically transparent materialconfigured to be positioned over the first and second light source. In afurther embodiment, the sterile cover further comprises a flexible bagcoupled to the rigid, optically transparent material.

The present invention is also embodied in a method of directing aninstrument from a surface to a target structure beneath the surface. Inone embodiment, the method includes emitting a first planar ultrasonicbeam in a first direction within a first plane, emitting a second planarultrasonic beam in the first direction within a second plane, projectinga first light line substantially within the first plane, projecting asecond light line within a third plane, aligning an end of theinstrument with a point of entry, aligning a length of the instrumentwith both a guide path and an angle of entry, and guiding the instrumentthrough the point of entry toward the target structure beneath thesurface, while substantially maintaining alignment of the length of theinstrument with both the guide path and the angle of entry. The secondplane and the third plane are both substantially perpendicular to thefirst plane. The third plane intersects the second plane at an obliqueangle and defines the angle of entry for the instrument. The first lightline defines the guide path for the instrument. The second light lineintersects and is substantially perpendicular to the first light line,and a point of intersection between the first light line and the secondlight line defines the point of entry for the instrument.

In one embodiment, the method includes displaying both a first imagefrom the first planar ultrasonic beam and a second image from the secondplanar ultrasonic beam. In a further embodiment, the second imageincludes a centerline. In another embodiment, the centerline correspondsto a center of the second planar ultrasonic beam. In yet anotherembodiment, the centerline corresponds to a point of intersectionbetween the first planar ultrasonic beam and the second planarultrasonic beam.

In one embodiment, the method includes aligning the second planarultrasonic beam over the target structure such that the centerline ofthe second image is substantially centered over the image of the targetstructure. In another embodiment, the method includes aligning the firstplanar ultrasonic beam over the target structure such that the targetstructure is visible in the first image while the centerline of thesecond image is substantially centered over the target structure.

In another embodiment, the method includes selecting the targetstructure on the first or second image. In a further embodiment, themethod includes selecting a desired angle of entry. In an additionalembodiment, the method includes selecting a desired point of entry onthe first image. In yet another embodiment, the method includesselecting both a desired point of entry on the first image and a desiredangle of entry.

In one embodiment, the method includes determining both a vertical and ahorizontal distance between the target structure and a light sourceprojecting the second light line. In one embodiment, the method includescalculating a projection angle of the light source required to projectthe second light line within the third plane such that the third planeis substantially incident a point of intersection between the secondplane and the target structure. The projection angle is defined by theequation α=arctan(y/x), where a is the projection angle, y is thevertical distance between the target structure and the light source, andx is the horizontal distance between the target structure and the lightsource. In another embodiment, the method includes rotating the lightsource so as to project the second light line within the third planesubstantially at the calculated projection angle.

In one embodiment, the method includes calculating a position of thelight source required to project the second light line within the thirdplane such that the third plane is substantially incident a point ofintersection between the second plane and the target structure. Theposition is determined from an equation tan α=y/x, where a is aprojection angle of the light source, y is the vertical distance betweenthe target structure and the light source, and x is the horizontaldistance between the target structure and the light source. In anotherembodiment, the method includes moving the light source substantially tothe calculated position.

In one embodiment, the method includes the step of calculating both aprojection angle and a position of the light source required to projectthe second light line within the third plane such that the third planeis substantially incident a point of intersection between the secondplane and the target structure. The projection angle and position aredetermined from an equation tan α=y/x, where α is the projection angle,y is the vertical distance between the target structure and the lightsource, and x is the horizontal distance between the target structureand the light source. In another embodiment, the method includesrotating the light source so as to project the second light line withinthe third plane substantially at the calculated projection angle, andmoving the light source substantially to the calculated position.

Other features and advantages of the invention should become apparentfrom the following description of the preferred embodiments, taken inconjunction with the accompanying drawings, which illustrate, by way ofexample, the principles of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a top-left perspective view of an ultrasound probe inaccordance with one embodiment of the present invention.

FIG. 2 is a front elevational view of an ultrasound probe in accordancewith one embodiment of the present invention.

FIG. 3 is a top plan view of an ultrasound probe in accordance with oneembodiment of the present invention.

FIG. 4 is a left elevational view of an ultrasound probe in accordancewith one embodiment of the present invention.

FIG. 5 is a bottom-left perspective view of an ultrasound probe inaccordance with one embodiment of the present invention.

FIG. 6 is a bottom plan view of an ultrasound probe in accordance withone embodiment of the present invention.

FIG. 7 is a top-left perspective view of an ultrasound probe in use inaccordance with one embodiment of the present invention, the ultrasoundprobe directing an instrument toward a surface.

FIG. 8 is a front-right perspective view of an ultrasound probe in usein accordance with one embodiment of the present invention, theultrasound probe directing an instrument toward a target structurebeneath a surface.

FIG. 9 is a left-back perspective view of an ultrasound probe in in useaccordance with one embodiment of the present invention, the ultrasoundprobe directing an instrument toward a target structure beneath asurface.

FIG. 10 is a left side elevational view of an ultrasound probe in use inaccordance with one embodiment of the present invention, the ultrasoundprobe directing an instrument toward a target structure beneath asurface at a first angle.

FIG. 11 is a left side elevational view of an ultrasound probe in use inaccordance with one embodiment of the present invention, the ultrasoundprobe directing an instrument toward a target structure beneath asurface at a second angle.

FIG. 12 is a top plan view of an ultrasound probe in use in accordancewith one embodiment of the present invention, the ultrasound probedirecting an instrument toward a surface.

FIG. 13 is a left side elevational view of an ultrasound probe inaccordance with one embodiment of the present invention, showing theultrasound probe on a surface in relation to a target structure.

FIG. 14 is a view of an ultrasound probe and a screen in use to directan instrument toward a target structure beneath a surface in accordancewith one embodiment of the present invention.

FIG. 15 is a front elevational view of an ultrasound probe with asterile cover in accordance with one embodiment of the presentinvention.

FIG. 16 is a left elevational view of an ultrasound probe with a sterilecover in accordance with one embodiment of the present invention.

FIG. 17 is a front elevational view of an ultrasound probe and foldedsterile cover, in accordance with one embodiment of the presentinvention, with the sides of the folded sterile cover being shown incross-section to reveal the folds.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

With reference now to FIGS. 1-6 of the illustrative drawings, there isshown an ultrasound probe 100 in accordance with embodiments of theinvention. In one embodiment, the ultrasound probe includes a housing105, a first ultrasonic transducer array 110, a second ultrasonictransducer array 115, a first light source 120, and a second lightsource 125.

In one embodiment, the first ultrasonic transducer array 110 and thesecond ultrasonic transducer array 115 are enclosed within the housing105, either directly or indirectly, and are substantially perpendicularto each other. In an additional embodiment, the ultrasonic transducerarrays are arranged in a T-shaped configuration. In a furtherembodiment, the ultrasonic transducer arrays can be configured in abiplane linear, multiplane, or 3D configuration. In another embodiment,the ultrasonic transducer arrays are configured as linear sequentialarrays, linear phased arrays, or curved sequential arrays.

The first light source 120 and the second light source 125 are coupledto the housing 105. Each of the light sources may be a laser or anyother light source capable of emitting a light line within a plane.

With reference to FIGS. 7-13, the first ultrasonic transducer array 110is configured to emit a first planar ultrasonic beam 111 in a firstdirection 113 within a first plane 112. The second ultrasonic transducerarray 115 is configured to emit a second planar ultrasonic beam 116 inthe first direction within a second plane 117. The second plane issubstantially perpendicular to the first plane. In one embodiment, thefirst and second planar ultrasonic beams may be swept ultrasonic beams.

The first light source 120 is configured to project a first light line121 substantially within the first plane. The second light source 125 isconfigured to project a second light line 126 within a third plane 127.The third plane is substantially perpendicular to the first plane andintersects the second plane at an oblique angle 128. The first lightline intersects and is substantially perpendicular to the second lightline.

The ultrasonic transducer arrays 110, 115 permit a user to visualize atarget structure 20 beneath a surface 10. For example, the ultrasoundprobe 100 may be placed on a patient's skin so as to emit the planarultrasonic beams 111, 116 through the skin toward a vein beneath theskin. As is well understood by a person of ordinary skill in the art,the transducer arrays are configured to collect reflected ultrasoundwaves and convert those sound waves into signals that can be used toproduce images of the area beneath the transducer arrays.

With reference to FIG. 14, in one embodiment, a screen 150 is coupled tothe ultrasound probe 100 and configured to display both a first image151 from the first ultrasonic transducer array 110 and a second image152 from the second ultrasonic transducer array 115. In an additionalembodiment, the screen is configured to display a centerline 153. In oneembodiment, the centerline corresponds to a center 118 (FIGS. 5 and 6)of the second ultrasonic transducer array. In another embodiment, thecenterline corresponds to a point of intersection between the firstultrasonic transducer array and the second ultrasonic transducer array.The screen may be coupled to the ultrasound probe directly orindirectly. For example, the screen may be coupled to the ultrasoundprobe via a WiFi radio, Bluetooth, Ethernet, USB, or other wired orwireless connection means.

Because the first and second ultrasound transducer arrays 110 and 115are configured to emit planar ultrasonic beams 111, 116 in the samedirection and within orthogonal planes, the ultrasound probe 100 can bepositioned on the surface 10 to provide simultaneous, longitudinal andtransverse images of the target structure beneath the surface. In oneembodiment, the longitudinal image is the first image 151, which isproduced by the first ultrasonic transducer array 110, and thetransverse image is the second image 152, which is produced by thesecond ultrasonic transducer array 115.

In use, this arrangement can permit a user to visualize the targetstructure 20 and the position of an instrument 30, such as a needle, inrelation to the target structure. More particularly, the first andsecond images 151, 152 and the optional centerline 153 can be used tofacilitate locating the target structure and following the instrument asit travels beneath the surface toward the target structure.

For example, it can be difficult to obtain and maintain a longitudinalimage of small arteries and nerves while it is relatively easy to obtainand maintain a transverse image of these small structures. Thecombination of the two images allows an operator to use the transverseimage as a tool to adjust the position of the ultrasound probe so as tomaintain a substantial length of the small artery or nerve within thelongitudinal image. More particularly, the operator can adjust theposition of the ultrasound probe 100 over the target structure 20 suchthat the centerline 153 of the transverse image is substantiallycentered over the target structure. Because, in one embodiment, thecenterline corresponds to a point of intersection between the firstultrasonic transducer array 110 and the second ultrasonic transducerarray 115, at least part of the target structure should be visiblewithin the longitudinal image closest to the transverse image. To finishalignment, the operator can pivot the ultrasound probe so that asubstantial length of the target structure is visible within thelongitudinal image.

With the ultrasound probe 100 so aligned over the target structure 20,the first and second light lines 121, 126 can be used as visual guidesto direct the instrument 30 from the surface 10 to the target structure20 beneath the surface. For example, when the first planar ultrasonicbeam 111 is aligned with the target structure, the first light line 121defines a guide path 121 for the instrument because it is substantiallywithin the first plane 112 of the first planar ultrasonic beam.

Similarly, the third plane 127 can be configured to define an angle ofentry 129 for the instrument 30, and the intersection 130 between thesecond light line 126 and the first light line 121 can define a point ofentry 130 for the instrument. As discussed above, the second light lineis projected within the third plane, which intersects the second plane117 of the second planar ultrasonic beam 116 at an oblique angle 128. Ifthe third plane intersects the second plane substantially at the pointwhere the second plane intersects the target structure 20, the thirdplane will define an angle of entry for the instrument 129.

With the ultrasonic probe so positioned and configured, the operator canalign an end of the instrument 30 with the point of entry 130, align alength of the instrument with both the guide path 121 and the angle ofentry 129, and guide the instrument through the point of entry towardthe target structure 20 beneath the surface 10 while substantiallymaintaining alignment of the length of the instrument with both theguide path and the angle of entry. In this way, the ultrasound probe 100can be used to direct an instrument from the surface to the targetstructure beneath the surface such that the instrument reaches thetarget structure substantially at the intersection of the first andsecond planar ultrasonic beams 111, 116.

Of course, with different target structures at different depths beneaththe surface (e.g., FIGS. 10 and 11), the third plane 127 may need to beadjusted so that it intersects the second plane 117 substantially at thepoint where the second plane intersects the target structure 20.Accordingly, in some embodiments, the second light source 125 may berotated or moved, relative to the first light source 120, so as tomodify the location or orientation of the third plane and the secondlight line 126 within that plane.

With reference again to FIGS. 7-13, in one embodiment, the second lightsource 125 is configured to project the second light line 126 within thethird plane 127 at a projection angle 129, wherein the projection angleis less than 90°. In an additional embodiment, a stepper motor (notshown) is coupled to the second light source. The stepper motor may becoupled to the second light source directly or indirectly. Withparticular reference to FIGS. 10 and 11, in a further embodiment, thestepper motor is configured to rotate the second light source andthereby adjust the projection angle, wherein the adjusted projectionangle is less than 90°.

With reference to FIG. 13, the projection angle 129 (or angle of entry),is defined by the equation α=arctan(y/x), where a is the projectionangle, y is the vertical distance 135 between the target structure 20and the second light source 125, and x is the horizontal distance 140between the target structure and the second light source.

In yet another embodiment, a position of the second light source 125,relative to the first light source 120, is adjustable. For example, thea position of the second light source may be adjustable, relative to thefirst light source, in a horizontal direction, a vertical direction, orboth, so that the third plane 127 intersects the second plane 117substantially at the point where the second plane intersects the targetstructure 20. In such a case, the position of the second light source isdefined by the equation tan α=y/x, where a is the projection angle 129of the second light source, y is the vertical distance 135 between thetarget structure and the second light source, and x is the horizontaldistance 140 between the target structure and the second light source.

With reference again to FIG. 2, in one embodiment, the ultrasound probe100 further includes a control panel 160. which may optionally comprisea touchscreen. In some embodiments, the control panel includes a powerbutton, a button to record the ultrasound images, and a button to recorda video of the real-time images being generated by the ultrasound probe.In another embodiment, the image power and contrast can be adjusted, aswell as the depth and angle of the target structure.

In a further embodiment, the control panel can include presets fordifferent procedures or individuals. These presets can be modified byindividuals and stored for future recall and use. For example, oneoperator may prefer to access a radial artery at 30°, while anotheroperator may prefer a steeper angle, such as 45°. In such a case, theoperators would select their preferred projection angle and set this asa preset value for future procedures.

With reference to FIGS. 15-17, in one embodiment, the ultrasound probe100 further comprises a sterile cover 165 coupled to the ultrasonicprobe 100. In an another embodiment, an ultrasound gel can be used withthe sterile probe cover 165 to optimize ultrasound transmission andoptimize image quality with minimum ultrasound power. In an additionalembodiment, the sterile cover 165 comprises a rigid, opticallytransparent material 165′, such as a hard plastic, configured to bepositioned over the first light source 120 and second light source 125.This rigid, optically transparent material can cover the light sourceswhile minimizing light distortion and attenuation. As such, the rigid,optically transparent material 165′ provides for a sterile environmentwhile maintaining the desired relationship between the light lines andthe planar ultrasonic beams. In an additional embodiment, the sterilecover 165 is secured to the ultrasound probe 100 by one or moreattachment points 166, which may be provided on the ultrasound probe,the cover, or both.

With particular reference to FIG. 17, in one embodiment, the sterilecover 165 further comprises a flexible bag 167 coupled to at least onepiece of rigid, optically transparent material 165′. In one embodiment,the rigid material 165′ is heat sealed onto the flexible bag 167. Themelted portion of the flexible bag will form over the rigid material amelted layer, which will not wrinkle or cause light distortion andattenuation when the light passes through it.

The flexible bag 167 can be folded over itself to create multiple foldchannels 170. FIG. 17 depicts a folded flexible bag 167, in accordancewith one embodiment, with the sides of the bag being shown incross-section to reveal the fold channels 170. The rigid material 165′is visible on the front side of the center pocket 171. In oneembodiment, the flexible bag further includes a guide portion 168, whichextends across the top of the folded flexible bag 167, from a peripheryof the flexible bag, into the center pocket 171. In an additionalembodiment, the guide portion is opaque and, therefore, obscures all butthe bottom of the center pocket 171 when viewed from above. Accordingly,the guide portion 168 can be configured to form a funnel leading to thecenter pocket 171. In this way, the guide portion facilitates placementof the ultrasonic probe 100 into the proper fold channel (i.e., centerpocket 171). In yet another embodiment, the guide portion 168 furtherincludes one or more tabs 169, which a user may pull to unfold theflexible bag 167 and draw it over the ultrasonic probe and its cable172.

In use, an operator would add ultrasound gel to the center pocket 171,place the ultrasonic probe 100 into the center pocket, align the rigid,optically transparent members 165′ over the first and second lightsources 120, 125, attach the rigid members 165′ to the ultrasonic probeat the attachment points 166, and pull the tabs 169 to draw the flexiblebag 167 over the ultrasonic probe.

In another embodiment, the ultrasound probe further includes a sterilescreen protector (not shown), which can permit an operator to interactwith the ultrasound probe under sterile conditions. In one embodiment,the screen protector can be held in place by a vacuum system (notshown), which maintains and supports the screen protector in place andstretches it to enable the use of optional touch screen features. Thevacuum system can be activated when the cover is placed on the screenand comes in contact with a sensor therein.

In a further embodiment, a reflective needle with depth guide isprovided as the instrument 30. Ultrasound reflectivity of the needle canbe enhanced to improve visualization of the needle as it approaches thetarget structure 20. In another embodiment, a surface of the needleincludes ultrasound reflectors. In an additional embodiment, the needleis etched at regular intervals. These markings can be used to indicatethe depth of the needle beneath the surface.

With reference again to FIGS. 7-14, the present invention is alsoembodied in a method of directing an instrument 30 from a surface 10 toa target structure 20 beneath the surface. In one embodiment, the methodincludes the steps of emitting a first planar ultrasonic beam 111 in afirst direction 113 within a first plane 112, emitting a second planarultrasonic beam 116 in the first direction within a second plane 117,projecting a first light line 121 substantially within the first plane,projecting a second light line 126 within a third plane 127, aligning anend of the instrument with a point of entry 130, aligning a length ofthe instrument with both a guide path 121 and an angle of entry 129, andguiding the instrument through the point of entry toward the targetstructure beneath the surface, while substantially maintaining alignmentof the length of the instrument with both the guide path and the angleof entry. The second plane and the third plane are both substantiallyperpendicular to the first plane. The third plane intersects the secondplane at an oblique angle 128 and also defines the angle of entry forthe instrument. The first light line defines the guide path for theinstrument. The second light line intersects and is substantiallyperpendicular to the first light line, and a point of intersection 130between the first light line and the second light line defines the pointof entry for the instrument.

With particular reference to FIG. 14, in one embodiment, the methodincludes displaying both a first image 151 from the first planarultrasonic beam 111 and a second image 152 from the second planarultrasonic beam 116. In another embodiment, the second image includes acenterline 153. In a further embodiment, the centerline corresponds to acenter 118 of the second planar ultrasonic beam. In yet anotherembodiment, the centerline corresponds to a point of intersectionbetween the first planar ultrasonic beam and the second planarultrasonic beam.

In one embodiment, the method includes aligning the second planarultrasonic beam 116 over the target structure 20 such that thecenterline 153 of the second image 152 is substantially centered overthe targets structure. In another embodiment, the method includesaligning the first planar ultrasonic beam 111 over the target structuresuch that the target structure is visible in the first image 151 whilethe centerline of the second image is substantially centered over thetarget structure.

In another embodiment, the method includes selecting the targetstructure 20 on the first or second image 151, 152. For example, thetarget structure can be either automatically or manually identified anda touch screen can be used to select the best path from the surface 10to the target structure. In a further embodiment, the method includesselecting a desired angle of entry 129. In an additional embodiment, themethod includes selecting a desired point of entry 130 on the firstimage 151. In yet another embodiment, the method includes selecting botha desired point of entry on the first image and a desired angle ofentry.

With reference to FIG. 13, in one embodiment, the method includesdetermining both a vertical 135 and a horizontal distance 140 betweenthe target structure 20 and a light source 125 projecting the secondlight line 126. In another embodiment, the method includes calculating aprojection angle 129 of the light source required to project the secondlight line within the third plane 127 such that the third plane issubstantially incident a point of intersection between the second plane117 and the target structure. The projection angle is defined by theequation α=arctan(y/x), where α is the projection angle, y is thevertical distance 135 between the target structure and the light source,and x is the horizontal distance 140 between the target structure andthe light source. In another embodiment, the method includes rotatingthe light source so as to project the second light line within the thirdplane substantially at the calculated projection angle.

In one embodiment, the method includes calculating a position of thelight source 125 required to project the second light line 126 withinthe third plane 127 such that the third plane is substantially incidenta point of intersection between the second plane 117 and the targetstructure 20. The position is determined from an equation tan α=y/x,where a is a projection angle of the light source, y is the verticaldistance 135 between the target structure and the light source, and x isthe horizontal distance 140 between the target structure and the lightsource. In another embodiment, the method includes moving the lightsource substantially to the calculated position.

In one embodiment, the method includes the step of calculating both aprojection angle 129 and a position of the light source 125 required toproject the second light line 126 within the third plane 127 such thatthe third plane is substantially incident a point of intersectionbetween the second plane 117 and the target structure 20. The projectionangle and position are determined from an equation tan α=y/x, where α isthe projection angle, y is the vertical distance 135 between the targetstructure and the light source, and x is the horizontal distance 140between the target structure and the light source. In anotherembodiment, the method includes rotating the light source so as toproject the second light line within the third plane substantially atthe calculated projection angle, and moving the light sourcesubstantially to the calculated position.

It should be appreciated from the foregoing description that the presentinvention provides an ultrasound probe that enables heath carepractitioners to safely perform procedures involving internal bodilystructures with greater ease and accuracy and fewer complications. Theultrasound probe can be used to reliably and continuously direct aninstrument from a surface to a target structure beneath the surface.

Specific methods, devices, and materials are described, although anymethods and materials similar or equivalent to those described can beused in the practice or testing of the present embodiment. Unlessdefined otherwise, all technical and scientific terms used herein havethe same meanings as commonly understood by one of ordinary skill in theart to which this embodiment belongs.

Without further elaboration, it is believed that one skilled in the art,using the proceeding description, can make and use the present inventionto the fullest extent. The invention has been described in detail withreference only to the presently preferred embodiments. Persons skilledin the art will appreciate that various modifications can be madewithout departing from the invention. Accordingly, the invention isdefined only by the following claims.

The invention claimed is:
 1. An ultrasonic probe comprising: a housing;a first ultrasonic transducer array coupled to the housing andconfigured to emit a first planar ultrasonic beam in a first directionwithin a first plane; a second ultrasonic transducer array coupled tothe housing and configured to emit a second planar ultrasonic beam inthe first direction within a second plane, which is perpendicular to thefirst plane; a first light source coupled to the housing and configuredto project a first light line within the first plane; and a second lightsource coupled to the housing and configured to project a second lightline within a third plane, which is perpendicular to the first plane andintersects the second plane at an oblique angle; wherein the first lightline intersects and is perpendicular to the second light line.
 2. Theultrasonic probe of claim 1, wherein the first light source is a firstlaser and the second light source is a second laser.
 3. The ultrasonicprobe of claim 2, wherein the first and second ultrasonic transducerarrays are arranged in a T-shaped configuration.
 4. The ultrasonic probeof claim 2, further comprising a screen coupled to the ultrasonic probeand configured to display both a first image from the first ultrasonictransducer array and a second image from the second ultrasonictransducer array.
 5. The ultrasonic probe of claim 4, wherein the screenis further configured to display a centerline.
 6. The ultrasonic probeof claim 5, wherein the centerline corresponds to a center of the secondultrasonic transducer array.
 7. The ultrasonic probe of claim 2, whereinthe second laser is configured to project the second light line withinthe third plane at a projection angle, wherein the projection angle isless than 90°.
 8. The ultrasonic probe of claim 7, further comprising astepper motor coupled to the second laser.
 9. The ultrasonic probe ofclaim 8, wherein the stepper motor is configured to rotate the secondlaser and thereby adjust the projection angle, wherein the adjustedprojection angle is less than 90°.
 10. The ultrasonic probe of claim 7,wherein a position of the second laser relative to the first laser isadjustable.
 11. The ultrasonic probe of claim 10, further comprising asterile cover coupled to the ultrasonic probe, wherein the sterile covercomprises a rigid, optically transparent material configured to bepositioned over the first and second light sources.
 12. The ultrasonicprobe of claim 11, wherein the sterile cover further comprises aflexible bag coupled to the rigid, optically transparent material. 13.The ultrasonic probe of claim 1, wherein, when the first light sourceand the second light source are projected on a surface of a subject, thefirst light source and the second light source act as visual guides fordirecting an instrument from the surface to a target structure beneaththe surface.
 14. The ultrasonic probe of claim 1, wherein, when thefirst ultrasonic transducer array and the second ultrasonic transducerarray are positioned against a surface, the first light line intersectsand is perpendicular to the second light line on the surface.
 15. Theultrasonic probe of claim 1, wherein the first and second light sourcesare configured to project the first and second light lines while thefirst and second ultrasonic transducer arrays are emitting the first andsecond planar ultrasonic beams.